ahoeben

Cura is a tool for slicing 3d models, ie to create gcode from models. It is not a tool for editing 3d models. Though you can do some edits in Cura, there are often better tools for that. Blender is free, but it is so powerful that it has a fairly steep learning curve.

Does the Ultimaker 2 family firmware have a "Reset to factory defaults" option? I think it does. Have you tried that?

Not every 3d model that is suitable for rendering (display) is suitable for 3d printing. The spokes are going to be really hard to print. Ofcourse you can try, but it would not be a question of loading the model and pressing slice, and then print. Looking at the details in the model, I would say "No, you cannot just purchase and print it with Cura on your Ender 5 Plus". Extensive work would be needed to think of strategies to print individual parts and putting them back together.

See the "Initial Layer Height" setting. Read more about it here: https://github.com/Ghostkeeper/SettingsGuide/blob/master/resources/articles/resolution/layer_height_0.md This is an article from the Settings Guide plugin, which is available from the marketplace.

Do you have a File, Edit, View, Settings and Preferences menu?

Also: what version were you using before? (so we can tell you where the features that you are missing went) That is probably because your GPU (or driver) does not support OpenGL 4.1

No, your firmware is not good at homing.

While not built in to Cura, you could write an automation script (eg a .bat, or .ps1) that pulls files from a central repository into the `user_changes and materials folders inside each user's configuration folders, before starting Cura. Come to think of it, that could be an interesting plugin to write.

Correct. But now you can set the nozzle size in the Machine Settings dialog.

Setting visibility also depends on values of settings. For example most of the settings for supports are hidden when you are not printing supports. In the last screenshot, see the little (i) icon? Hover over it, and it will give you (some) reason why this setting can not be made visible. The monotonic setting is not available when the Top Layers and Bottom Layers settings are both at 0 (there's nothing to print monotonically), or when the "Top/Bottom Pattern" setting is set to "Concentric" (concentric is already as monotonic as it will ever be).

You could add this to the end of your start gcode: G0 X0 Y0 ;go to where the printer thinks home is G92 Z4.5 Y1 ;tell the printer it is actually at X 4.5 and Y 1 G0 X0 Y0 ;go to where the printer thinks home is now

Are you using the AppImage as provided by Ultimaker, or a different version? Try the AppImage. The version of Cura you use now is crashing while trying to tell you that it cannot initialize an OpenGL context; not even an OpenGL 2.0 context. The crash itself is likely caused by a version-mismatch in a dependency. The AppImage comes with the right versions of dependencies integrated. Your system not being able to initialize an OpenGL context is more indicative of a driver issue, as mentioned by @gr5

For the benefit of others finding this question after having this problem, or for people like me who like helping other people with the same issue, how did you solve the problem?

You can use this list, if you remove the {} around the setting names, and ignore the "Application-defined patterns": http://files.fieldofview.com/cura/Replacement_Patterns.html This page is actually generated from this file (which is part of Cura): https://github.com/Ultimaker/Cura/blob/master/resources/definitions/fdmprinter.def.json

This is (probably) a macOS-specific bug in the Qt GUI framework that Cura uses. It is likely fixed in the Qt version that will be used in the next version of Cura (Cura 5).

That is just how you have (inadvertently?) configured your Windows installation. In windows, file types are discerned by the extension of the filename. This extension is typically hidden by Windows, but it is part of the filename. Cura has no control over what filetype Windows has configured for a file with a certain extension. Fortunately, it does not affect how the gcode file is printed; your printer does not care about what type of file Windows thinks a .gcode file is. Here's an article about changing the file association in Windows 10: https://fileinfo.com/help/windows_10_change_file_associations

You are going to have to clarify what you mean by "it saves it as the download on the internet". I have no idea what you mean by that.

Cura does not know what it means. It is just what the OS says to Cura, when Cura attempts to write the file. If I would know what OS you use, I would Google what error 13 means for that OS. Without knowing your OS (and Google), I can only guess. A somewhat safe guess is that the OS is telling Cura that there are insufficient user privileges to write (or overwrite) a file, or that you are trying to write to a read-only location (eg an SD-card which has its write-protection switch turned on).

An STL file does not support multiple "bodies". In the STL file, your objects become one combined mesh, even if not all parts of that mesh are connected. They are not so much grouped, they are one mesh. That is why you cannot ungroup. The Mesh Tools plugin, available from the Marketplace, adds a function to split such meshes that consist of multiple "non-connected parts".

I thought perhaps there was a UTF-8 "BOM" in the gcode file that could interfere with the firmware checking if the file starts with ";FLAVOR:UltiGCode", but alas, there is no such thing in the provided gcode file.

It should not be doing that. That would actually be very helpful. The problem is that we cannot reproduce this issue. So we don't know "what the hell it is doing". And when we don't know what it is doing, we cannot stop it from doing it.

The Marketplace only contains material profiles for Ultimaker printers. Ultimaker printers use 2.85 mm materials, and since your printer uses 1.75 mm materials, the materials you download from the Marketplace are not shown for your printer.

If you mean the layer that is currently printing, then no. There is no way to show that in Cura.

With issues like this where there are multiple displays in play, it is also worth the effort to try unchecking the option "Restore window position on start" in the General preferences in Cura.

See the "Skin Removal Width" setting: https://github.com/Ghostkeeper/SettingsGuide/blob/master/resources/articles/top_bottom/skin_preshrink.md